(1) Field of the Invention
The invention relates to, in combination, a device for cleaning fire tubes in a boiler, comprising a scraper member that is fixed to a movement member for moving said scraper member through one fire tube at a time, a guide for positioning the scraper member directly in front of the open end of a fire tube such that this is movable from the guide into the fire tube and conversely from the fire tube into the guide, as well as a boiler provided with fire tubes, which fire tubes open at one end of the boiler, wherein the guide is movable transversely with respect to the longitudinal direction of the fire tubes on a frame that is located at the end of the boiler where the fire tubes open, and wherein a flue box is located at the end of the boiler where the fire tubes open, which flue box has openings that are each located opposite a fire tube.
(2) Description of the Related Art
A device for cleaning fire tubes is disclosed in GB-A 253 816. In this known device the guide can be fitted opposite a fire tube by means of a screw connector such that the scraper member, such as a wire brush, can then be moved to and fro through said fire tube to remove contaminants. After the fire tube has been cleaned in this way, the guide is removed and then screwed in at the location of the following fire tube to be cleaned. The cycle is repeated in this way until all fire tubes to be cleaned have been treated. What is important is that, if unhealthy working conditions have to be avoided, this device can be used only when the boiler is not in service.
Such a state of affairs is laborious and labour-intensive, which is associated with high costs. Moreover, such activities are dirty and unattractive; a further disadvantage is that according to ARBO (Health and Safety at Work) legislation the boiler has to be taken out of service before carrying out the work.
EP-A 967 452 discloses a combination of a cleaning device and a boiler, where the guide can be moved on a frame transversely to the longitudinal direction of the fire tubes. As a result the fire tubes of the boiler can be cleaned more efficiently.
Because the guide is mounted on a frame, this has a stable support and it is no longer necessary to screw in the guide at the location of each fire tube. Treatment of the boiler can consequently be automated. However, the frame for moving the guide extends into the flue chamber. A high temperature prevails in the flue chamber and the flue gases give rise to an aggressive environment. As a result the movement system can develop a fault and the life will be shortened.
Furthermore, the movement member for moving the brush is constituted by a flexible drive element that is guided in a sleeve in the form of a hose. This movement member can reach each fire tube from a single inlet in the flue box, that is to say the movement member traverses a different curved path for each fire tube. As a result, wear will rapidly occur in the hot and dirty flue box, so that this flexible drive element is relatively unreliable.
Furthermore, pushing the drive element though a fire tube that is not located in the centre will lead to kinking, in particular for boilers with a diameter of 2-5 meters or more. As soon as kinking occurs, the force that is needed to push the brush through the fire tube can no longer be exerted.
The aim of the invention is to provide a combination of a cleaning device and a boiler that enables automatic treatment of the boiler, wherein the reliability is increased.
Said aim is achieved according to the invention in that there is a flue box at the end of the boiler where the fire tubes open, which flue box has openings that are each located opposite a fire tube and are each provided with a closing valve and the device is provided with an operating mechanism that can be brought into interaction with one of the closing valves in each case for opening said closing valve.
By using closing valves for openings in the rear plate of the flue box it is possible to position the frame completely outside the flue box. As a result, the hot and aggressive conditions in the flue box will not have an adverse effect on the functioning of the frame and the movement of the scraper member. The reliability is improved by this means. In addition, the interaction between the closing valve and the operating mechanism ensures that cleaning of the fire tubes can be automated.